Qantas v TWU is a restructuring case with a hard workplace-law edge. A business can have real commercial reasons to outsource, automate or restructure. The problem is when the decision record also shows a substantial reason connected to stopping employees from using workplace rights, such as protected industrial action or bargaining rights that may arise later.
For business owners, the useful lesson is discipline. If you are making a major workforce decision, write down the commercial reasons clearly, keep the people involved aligned, and get advice before employee rights, bargaining, union activity or protected action are part of the background.